Lecture 17 Flashcards Preview

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Flashcards in Lecture 17 Deck (29):
1

Why isn't there communal immunity to the 60 variants of the PfEMP1 protein?

There is variation within the 60 copies

This is due to ectopic recombination

2

Recombination between heterologous chromosomes is Malaria's way of

generating rapid diveristy in var genes

3

Chromosomes are usually found in _ clusters with Malaria cells

4

4

The alignment of genes in groups of 4-5 allows for.....

ectopic recombination

5

True or False

Every time there is a blood life cycle of Malaria there is more recombination going on that normal amounts.

Leads to different looking var genes

True

6

Plasmodium parasites export 100's of proteins into RBC cytosol, What is their main role?

Crucial virulence and nutrient uptake roles

7

An example of plasmodium protein is KAHRP, when knocked out...

cells were smooth

parasites don't adhere to vascular endothelium

can't hold on in physiological flow pressure

An example of the importance of exporter proteins, one of hundreds

8

The PEXEL motif (a string of AAs) is a...

cleavage site that is recognised in the ER by an enzyme known as Plasmepsin V

9

___% of exported genes are essential to growth (can't be knocked out)

25%

10

If the cleavage occurred in the ER, by PEXEL, proteins follow a very particular _____ pathway and dumped their proteins into a specific place

If the cleavage occured in the ER, by PEXEL, proteins follow a very particular vesicular pathway and dumped their proteins into a specific place

11

What are the essential things of a putative Plasmodium translocon of PEXEL proteins = PTEX?

(PTEX is the machinery PEXEL proteins recognise on the parasite membrane)

Plasmodium specific and in the correct location

Essential to blood-stages

Energy source, an un-folding mechanism

Binds transiting cargo PEXEL proteins

12

EXP2 forms the ___ of PTEX

pore

13

Anti-malarial drugs can target >..

PTEX

14

What are the 3 types of Malarial vaccines in development?

1. Pre-erythocytic (prevent infecting the liver). RTS,S is on phase 3 clinical trial

2. Transmission blocking - to protect mosquito, gives antibodies to mosquito when it bites

3. Blood- - Anti-meroziote antibodies

15

True or False

Different Plasmodium species prefer different RBCs

True

16

Plasmodium _______ recognises all RBCs, old and young - not all like all other species of Malaraia

Plasmodium falciparum recognises all RBCs, old and young - not all like all other species of Malaraia

17

parasite Cells are outside of other cells for about ____ during invasion

1.5 minutes

18

Looking at Blood-stage vaccine

Antigens have been idnetified but _____ is not well known for each

function

19

The RBC surface us highly _______

polymorphic - very hereogenous

e.g none of west africe expresses the Duffy glycoprotein, the rest of the world does

20

Duffy glycoprotein, essential for plasmodium vivax to...

enter RBCs

21

Instead of just one or two secondary ligands bein responsible for binding RBCs there are at least _

8

22

Plasmodium falciparum however has a lot of different _____ that can bind to different receptors

Ligands

23

True or False

Parasites can switch their invasion henotype, can alter receptor/ligand usage

True

24

What happens if you delete the ligand EBA175 used by W2mef?

You get a transcriptional switch, no longer expresses EBA175, it expresses another evasion ligand called Rh4

25

True or False

A single parasite, genetically identical, can switch the ligand it expresses to enter RBCs

True

26

The different ligands ecode for different receptor binding characteristics - this is a problem for...

vaccine development

27

Alternate invasion pathways allow parasites to invade via a diverse range of RBC receptors and to avoid ________

immunity

28

EBA and Rh proteins are important targets of inhibitory ________

antibodies

29

At least _ pathways for invasion need to be covered for a vaccine to work

3